Are you referring to the soft keys? That is completely sensor related. Upper right corner is the light sensor. Put hand over it and lights will come back on. Not sure if something has changed or not since 2.0.1 but mine tend to act the same.
I say this but it is sensor related if auto brightness is used. At least in my findings. In auto brightness it will cut off the lights. I personally do not have this issue since I dont use auto brightness so I dont believe it is 2.0.1 related.
Oh yeah...I am also rooted and over clocked but nothing has changed there. Something in your settings or an app is causing this.
2.0... light on home keys stayed on no matter what... with auto brightness turned off.
2.0.1..... turns off when in bright areas. Sensors in camera and front affect it upon my testing. One day my home lights would stay on even if I covered the camera lens while in a bright area with the front sensor exposed. The next day the exact opposite. Faced the camera into the light and covered the front sensor and the home light stayed on. Now if either sensor senses a bright light... it turns it off.